Physiology of hypothalamic neurosteroidal progesterone

 描述(申请人提供)：神经类固醇，在大脑中重新合成的类固醇，与从应激到抑郁、焦虑和认知的一系列功能有关。黄体酮是一种神经类固醇，它是一种与生殖调节有关的经典性激素。我们之前已经证明，外周雌二醇(E2)增加了下丘脑神经孕酮(NeurOp)的合成，从而启动了黄体生成素(LH)的激增。黄体生成素激增触发排卵和卵巢卵泡破裂的黄体化--这是生殖过程中的关键事件。这种雌激素正反馈是由下丘脑室周头侧核(RP3V)的Kispeptin神经元调节的。我们建议使用永生化的雌性成年小鼠下丘脑Kispeptin神经元，mHypoA-51s，来研究黄体生成素激增背后的E2和NeurOp信号。初步资料表明，mHypoA-51细胞系是RP3V-Kispeptin神经元的良好模型：两者都有雌激素受体-α(ER-α)、孕激素受体(PR)和Kispeptin。与天然的Kispeptin神经元一样，mHypoA-51s中的E2诱导Kispeptin和PR的表达，并将其运输到细胞膜。令人惊讶的是，随后用P4或星形胶质细胞条件培养液刺激mHypoA-51s可诱导钙释放并增加Kispeptin的表达。我们的总体假设是，雌激素诱导的PR介导了Kispeptin神经元的NeurOp激活，从而诱导了LH峰。将在体外和体内测试三个假设，以表征雌激素正反馈下雌激素和孕激素信号的整合：(1)核ERα诱导PR，PR被NeurOp激活；(2)膜上定位的PR的NeurOp激活刺激Kispeptin的释放；(3)Kispeptin神经元中的NeurOp信号调节LH峰。这些拟议的研究将共同测试中枢神经系统中孕酮信号的一种新机制，通过这种机制，外周和中枢类固醇信息的整合调节生殖。

 DESCRIPTION (provided by applicant): Neurosteroids, steroids synthesized de novo in the brain, have been implicated in functions ranging from stress to depression, anxiety, and cognition. One neurosteroid is progesterone, a classic sex hormone involved in the regulation of reproduction. We have previously shown that peripheral estradiol (E2) increases hypothalamic neuroprogesterone (neuroP) synthesis, which initiates the luteinizing hormone (LH) surge. The LH surge triggers ovulation and the luteinization of the ruptured ovarian follicle - critical event in reproduction. This estrogen positive feedback is regulated by kisspeptin neurons of the hypothalamic rostral periventricular nucleus (RP3V). We propose to use immortalized, female, adult mouse hypothalamic kisspeptin neurons, mHypoA-51s, to examine the E2 and neuroP signaling underlying the LH surge. Preliminary data indicate that mHypoA-51 cell line is a good model for RP3V kisspeptin neurons: both have estrogen receptor-α (ERα), progesterone receptor (PR) and kisspeptin. Like native kisspeptin neurons, E2 in mHypoA- 51s induces expression of kisspeptin and PR, which is trafficked to the membrane. Surprisingly, subsequent stimulation of mHypoA-51s with P4 or astrocyte conditioned media induces calcium release and augments kisspeptin expression. Our overall hypothesis is that E2 induced PR mediates neuroP activation of kisspeptin neurons to induce the LH surge. Three sub-hypotheses will be tested in vitro and in vivo to characterize the integration of estrogenic and progestational signaling underlying estrogen positive feedback: (1) nuclear ERα induces PR, which is trafficked to the membrane and activated by neuroP; (2) neuroP activation of membrane localized PR stimulates kisspeptin release; and (3), neuroP signaling in kisspeptin neurons regulates the LH surge. Together the proposed studies will test a novel mechanism of progesterone signaling in the CNS, through which integration of peripheral and central steroidal information regulates reproduction.